How do I delete time machine backups from my NAS?

Hi still new to Mac OS X, I am normally a Linux guy, and since Linux and Mac are both Unix based. I figured I'd give it a shot when the company gave me a Macbook Pro to use as my work and personal laptop a few months ago.
Well anyway since then I have done a lot of time machine backups from all the files I change on the 750GB hard drive I installed, this was before Apple had a 7200RPM 750GB option. Which by the way I love how easy it was to transfer to a new hard drive. Nothing fancy just transfer all the data to an external with my new hard drive, then swap drives and voila. And time machine has saved my butt on quite a few occasions.
Well I have a Seagate blackarmor 2TB NAS device to back up my Macbook Pro, and my fathers Macbook Pro. But my backups are taking about 1TB from all the changes. Is there anyway to delete only my backups and not my fathers from the time machine part of the NAS? Because I want to have a new time machine backup from scratch.

Should be easy enough to do. When Time Machine backs up to a network device such as a NAS it stores the files in a sparsebundle file (essentially a single disk image file that grows as more space is needed.

Navigate to your NAS and look for an image file for your computer. The file usually has the same name as your computer. If you're not sure of the computer name open the Sharing preference pane one System Preferences. The name will be there. Find the image file on your NAS and delete it.